Integrated circuit manufacturers use inspection systems to detect anomalies, such as defects, in substrates. Generally, an inspection system rasters the surface of the substrate with one or more optical sensors, and generates image data based on the images detected by the sensors. This image data is analyzed according to one or more of a variety of different algorithms to determine where defects might exist on the substrate. Integrated circuit manufacturers demand that such inspection systems meet several criteria. Among these criteria is that the inspection system must be extremely accurate, fast, and reliable. Further, such inspection systems should preferably be reasonably priced and relatively flexible.
Prior art inspection systems have implemented one or both of pipelined systems or computers that are networked in a switched fabric topology, which use highly customized hardware. Customized hardware has several disadvantages as compared to commercially available hardware, including higher nonrecurring engineering costs for the developer, lower reliability, longer development times, and more inflexibility in changing algorithms. Switched fabric systems have additional disadvantages, including high cost, lack of standards between manufacturers, and development lag in the components, such as the level of microprocessor that is built into such systems.
Previous approaches to these problems have provided just one of either relatively high bandwidth or relatively low bandwidth interconnects between all of the processors of a system. The relatively high bandwidth approaches can work, but may be more expensive than necessary. The relatively high speed data interconnect in a supercomputer can be a significant portion of the overall system cost. For some applications, exclusive use of a relatively high speed interconnect is excessive. Examples of relatively high bandwidth networks include the SKY and Mercury computer system computers with SKY channel, Infiniband, Race++, or RAPIDIO interconnections.
Relatively low bandwidth approaches may be insufficient to handle the bandwidth requirements of the desired applications. An example of a relatively low bandwidth interconnect is a Linux cluster based around the BEOWULF strategy, with a simple 100 base-T Ethernet interconnect fabric. The old techniques either provide insufficient interconnect bandwidth to successfully complete the problem, or supply an excessive amount of interconnect bandwidth at too great a cost
What is needed, therefore, is a system that overcomes problems such as those described above, at least in part.